A variety of 7.alpha.-lower alkoxycephalosporins of the general formula ##STR1## especially those wherein the lower alkoxy group is methoxy, have been disclosed to be useful antibacterial agents. See, for example, Belgian Pat. No. 768,528 and Netherlands patent publication No. 72.04982. Valuable intermediates for the production of these products are those cephalosporins wherein there is a sulfur group in the 7-position, a radical which is replaceable by the alkoxy group. It is an object of this invention to provide an improved process for synthesizing such products by means of novel intermediates.